Abstract Physical properties of non durable woods with a low temperature pyrolysis treatment.
Wood pyrolysis at low temperature results in a solid product intermediary between
wood and charcoal: torrefied wood. The aim of this study was the optimisation
of the process and the determination of the material end-use properties
and utilisation limits. Residence times, final temperature and atmosphere
were the process parameters studied. Some characteristics were measured to describe
physical and mechanical behaviour of the material: moisture content, anti-shrink
efficiency, compression and bending strength, modulus of elasticity. Resistance
to different biological decay agents (fungi and insects) was also measured to
estimate the durability conferred by the thermal treatment. The results show that
the properties of the material are very sensitive to the process parameters,
in particular the residence time and the presence of water vapour in the atmosphere.
The thermal treatment must be adapted to the wood species and a compromise must be
found in the treatment between mechanical properties on one hand and dimensional
stability and durability on the other hand.